This lecture is part of an online course on algebraic topology. This is an introductory lecture, where we give a quick overview of some of the invariants of algebraic topology (homotopy groups, homology groups, K theory, and cobordism). The book "algebraic topology" by Allen Hatcher mentioned in the video can be downloaded from the author's page https://pi.math.cornell.edu/~hatcher/ For the other lectures in the course see    • Algebraic topology